bug#5605: etags of emacs 23.1 misses template specializations

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Thu, 03 Jun 2021 11:15:35 +0200
> Cc: 5605@debbugs.gnu.org
> 
> "Bob" <purchasebyemail1@comcast.net> writes:
> 
> > Run "etags" of emacs 23.1 on the attached "Foo.H" file . 
> >
> > The resulting TAGS file indicates "Foo.H" is empty.
> >
> > Seems to me it should show two definitions for the 2 specializations of 
> > `Worker`. 
> 
> (I'm going through old bug reports that unfortunately got no response at
> the time.)
> 
> I don't know whether it should or not, but the behaviour of etags in
> Emacs 28 is still the same -- it produces an empty TAGS file.

'etags's support for templates is very rudimentary, it doesn't
currently identify a class if its name is followed by <foo,bar>.
Patches welcome.